谷氨酸钠致痫大鼠海马mGluR5的表达变化

本研究目的为探讨谷氨酸钠(GluNa)诱导大鼠癫痫发作时海马mGluR5的表达变化。将动物随机分为正常对照组、Glu—Na致痫组及D—AP-5(非竞争性：NMDA受体拮抗剂) GluNa组。通过免疫组织化学方法观察了多克隆抗体抗mGluR5在海马各区及齿状回的免疫反应阳性细胞的变化，同时观察并记录各组大鼠的行为变化。结果证明：GluNa注射后的大鼠均出现严重的癫痫发作。正常组大鼠海马中有丰富的mGluR5表达，以齿状回颗粒细胞层和CA1锥体细胞层的表达为最高，而GluNa致痫组海马各区mGluR5表达明显下调。D—AP-5 GluNa组海马各区mGluR5表达较之GluNa致痫组又上调。同时观察到三个组的mGluR5的表达主要集中在细胞膜上。结果提示mGluR5在癫痫发作后表达下降可能在癫痫诱导过程中具有重要作用，其作用机制可能为NMDA受体依赖性的。     

IL-1β对谷氨酸钠致痫大鼠海马代谢型谷氨酸受体5的表达的影响

目的：探讨IL-1β对谷氨酸钠(GluNa)致痫大鼠海马代谢型谷氨酸受体(mGluR)5的表达变化的影响。方法：把大鼠随机分为生理盐水组、GluNa组、IL-1β GluNa组、人重组IL-1受体拮抗剂(rhIL-1ra) IL-1β GluNa组及D-AP-5(非竞争性NMDA受体拮抗剂) IL-1β GluNa，利用免疫组织化学并结合图像分析进行研究。结果：Glu-Na注射后的大鼠均出现严重癫痫发作。mGluR5表达在生理盐水组大鼠海马中丰富，GluNa致痫组则明显下调，IL-1β GluNa组比GluNa组明显下调，rhIL-1ra IL-1β GluNa组和D-AP-5 IL-1β GluNa组比IL-1β十GluNa组明显增加。同时观察到3个组的mGluR5的表达主要集中在细胞膜上。结论：mGluR5在癫痫发作后表达下降可能在癫痫诱导过程方面具有重要作用，其与IL-1β受体之间可能存在相互作用。     

白细胞介素-1β对谷氨酸钠致痫大鼠海马Gs蛋白表达的影响

目的 探讨白细胞介素-1β(Interleukin-1，IL-1β)在谷氨酸钠致痫大鼠中对海马兴奋性G-蛋白α亚基(stimulated G-protein α subunit，Gsα)蛋白表达的影响，为阐明IL-1β在致痫中的作用机制提供线索。方法 免疫组织化学方法结合行为观察(SD大鼠随机分为对照组、GluNa组、IL-1β GluNa组、rhIL-1ra IL1β GluNa组和D-AP-5 IL-1β GluNa组)。结果 行为观察显示，IL-1β GluNa组大鼠痫性发作潜伏期(平均2min)较其他组(平均6min)明显缩短，且发作程度(Ⅲ～Ⅳ级)较其他组(Ⅰ～Ⅲ级)严重；对照组无痫性发作。免疫组织化学染色显示，Gsα蛋白在海马各区均有表达，IL-1β GluNa组大鼠在齿状回、CAl区和CA3区Gsa表达较其他组明显增强。结论 IL-1β参与致痫，且在谷氨酸致痫中可能通过Gs蛋白介导发挥作用。     

NMDA受体1和雌激素受体在白细胞介素-2致痫大鼠脑内的表达变化和共存

目的 探讨白细胞介素2(IL-2)致痫与NMDA受体(NMDAR)和雌激素受体(ER)的关系.方法 应用免疫组织化学、免疫荧光双标和激光共焦显微镜技术研究IL-2致痫大鼠及经免疫抑制剂预处理后再致痫大鼠脑内NMDAR-1、ER的表达变化以及NMDAR/ER和NMDAR/IL-2R共存情况.结果 大鼠侧脑室注射IL-2以后,动物出现明显的癫痫发作,其大脑皮质和海马部位NMDAR-1及ER表达较对照组明显增多,免疫反应平均吸光度(A)值与对照组相比有极显著性差异;而用IL-2抑制剂环胞霉素(CsA)或糖皮质激素(G)预处理后再注射IL-2,动物未出现或仅出现轻微的癫痫发作,其NMDAR-1和ER表达较IL-2组明显减少(P＜0.05).研究还观察到大鼠脑内大脑皮质和海马部位NMDAR/ER或NMDAR/IL-2R之间存在着广泛共存.结论 IL-2有致痫作用,NMDAR-1、IL-2R和ER在致痫活动中可能存在协同和互动作用.     

白细胞介素-1β或白细胞介素-6致痫大鼠脑内γ-氨基丁酸和谷氨酸免疫反应性的变化

目的研究白细胞介素-1β（IL-1β）和白细胞介素-6（IL-6）致痫过程中谷氨酸（Glu）和γ-氨基丁酸（GABA）在大脑皮质及海马内表达的变化,探讨IL-1β及IL-6在癫痫发病中的作用机制。方法大鼠随机分为生理盐水对照组、IL-1β组、IL-6组,侧脑室注射相应试剂120min后观察大鼠行为变化,并采用免疫组织化学方法检测大脑皮质及海马内Glu及GABA的表达变化。结果动物行为学观察,生理盐水对照组无明显癫痫发作,IL-1β组、IL-6组发作程度达中度。免疫组织化学染色显示,在注射IL-1β或IL-6 120min后,IL-1β、IL-6组Glu表达在大脑皮质及海马较对照组明显升高,GABA表达较对照组明显降低,差异显著。结论IL-1β或IL-6可能通过升高Glu含量并降低γ-氨基丁酸的含量参与促痫和致痫过程,从而使神经元兴奋性升高促进癫痫发作。     

IL-1β对谷氨酸致痫大鼠大脑皮质、海马内NMDAR_1免疫反应变化的影响

为了进一步探讨 IL -1β在促进癫痫发作中的机制 ,用免疫组织化学方法比较了单纯用致痫量谷氨酸钠致痫的大鼠和预先向侧脑室注射 IL-1β再用阈下剂量的谷氨酸钠共同致痫的大鼠脑内 NMDAR1 免疫反应的变化。结果表明 ,IL-1β和谷氨酸钠共同致痫的大鼠大脑皮质及海马 CA3区 NMDAR1 免疫反应较对照组明显增强 (P<0 .0 5 ) ,与单纯用谷氨酸钠致痫的大鼠没有明显区别。如果预先给予 IL-1ra或 D-AP5则 IL-1β和谷氨酸钠的共同致痫效果不出现 ,脑内 NMDAR1 免疫反应与对照组比较未见明显增强 (P>0 .0 5 )。本实验结果表明 ,IL -1β具有促进癫痫发作的效应 ,这种促癫痫效应的发挥与谷氨酸受体具有协同作用 ,并与通道型 NMDA受体 R1 亚单位表达的增加有关     

马桑内酯致痫大鼠海马神经元丢失及化学性质的研究

为观察癫痫发作过程海马神经元丢失细胞的主要死亡方式 ,用马桑内酯建立慢性致痫大鼠模型 ,以 Nissl染色、免疫组化、TUNEL法以及后二者相结合的技术 ,对海马神经元及其中的抑制性神经元的丢失进行了分区观察、统计、分析。结果发现 :致痫组海马各区神经元较对照组明显减少 ,不同区域减少程度不同 ,以齿状回减少最为明显 ;免疫组化结果显示 ,致痫组的抑制性神经元 GABA-IR神经元、PV-IR神经元、CB-IR神经元在海马各区有不同程度的减少 ,其中 GABA-IR神经元减少最明显。在海马各区所有丢失的神经元中 ,三种抑制性神经元所占的比例不同 ;并在海马各区均可见到 TUNEL -GABA、TUNEL-PV、TU NEL-CB双重反应阳性神经元。提示 :马桑内酯所致的癫痫发作 ,可引起海马神经元丢失 ,且不同区域丢失的程度不同 ,丢失的神经元可能以凋亡方式为主 ;海马抑制性神经元 GABA-IR、PV-IR、CB-IR神经元在癫痫发作过程中也有不同程度的丢失 ,丢失很可能也是以凋亡形式为主     

氯喹对戊四氮慢性致痫大鼠海马GluR2及nNOS表达的影响

目的:观察氯喹对戊四氮慢性致痫大鼠海马α-氨基羟甲基异恶唑丙酸(amino-3-hydroxy-5-methylisox-azole-4-propionic acid,AMPA)受体(GluR2)及神经型一氧化氮合酶(nitric oxide synthase,nNOS)表达的影响,探讨氯喹在癫痫发生发展中的作用。方法:30只健康雄性SD大鼠,随机分为3组:对照组(10只)、戊四氮致痫组(10只)、氯喹干预组(10只),观察大鼠行为表现和脑电图的改变。应用Western Blot检测大鼠海马GluR2含量的改变,免疫组化检测nNOS的变化。结果:对照组无癫痫发作,戊四氮致痫组癫痫发作严重(III~Ⅴ级),氯喹干预组痫样发作与戊四氮致痫组相比较轻(Ⅰ~III级,P<0.05);戊四氮致痫组脑电记录呈频发高幅的痫样波,氯喹干预组痫样波幅低且缓;与对照组相比,癫痫组GluR2表达减弱(P<0.05),氯喹干预组与对照组比较差异有显著性(P<0.05);nNOS在戊四氮致痫组表达强,以海马为著,与对照组比较差异有显著性(P<0.05),氯喹干预组与对照组比较无显著性差异(P>0.05)。结论:氯喹可以通过调节GluR2的含量和抑制nNOS的表达,表明氯喹可能是预防和治疗癫痫的理想药物。     

白细胞介素1β对谷氨酸致痫大鼠海马mGluR2和mGluR3 mRNA表达的影响

目的 探讨IL-1β对谷氨酸(Glu)致痫大鼠mGluR2和mGluR3 mRNA表达的影响。方法 将大鼠分为对照组；Glu组；IL-1β Glu组；IL-1β组；IL-1β D-AP5 Glu组，观察大鼠的行为变化，用RT-PCR半定量分析mGluR2和mGluR3 mRNA的表达。结果 IL-β Glu组大鼠的痫性发作潜伏期比Glu组明显缩短，发作程度也较重；mGluR2和mGluR3 mRNA在IL-1β Glu组和Glu组中的表达比其他组都显著增强，而mGluR2mRNA在IL-1β Glu组的表达与Glu组比较明显下降，mGluR3的表达在这两组中无明显差别。结论 IL-1β可能通过下调mGluR2的表达而促进癫痫发作。     

mGluR7在氯化锂-匹罗卡品反复致癎大鼠海马的表达及作用

目的:通过氯化锂-匹罗卡品反复致癎大鼠模型,探讨代谢型谷氨酸受体7(mGluR7)在癫癎发作过程中的作用。方法:大鼠分为正常对照组和模型组,用氯化锂-匹罗卡品制作癫癎模型,将模型组中致癎成功鼠分为反复刺激组和静止期组,致癎不成功作为不成功组。制作冰冻切片用免疫组化法检测4组大鼠海马CA1、CA3区及齿状回mGluR7光密度值。结果:与正常对照组相比,静止期组大鼠海马各区表达均减弱,以齿状回差别最明显,反复刺激组各区表达均明显增强,不成功组无明显改变。结论:mGluR7表达上调提示癫癎多次发作可能增强了其对谷氨酸释放的负反馈调节和摄取作用; mGluR7在静止期表达下调提示其可能有助于慢性期癫癎环路的形成。     

Synaptic plasticity in the adult visual cortex is regulated by the metabotropic glutamate receptor, mGLUR5

In the intact adult animal, synaptic plasticity in the visual cortex (VC) is a dynamic and naturalistic phenomenon, the mechanisms of which are not yet fully understood. Given its intrinsic role in hippocampal plasticity, we investigated the effects of pharmacological antagonism of mGluR5 on synaptic plasticity and receptor expression in the VC of freely moving adult pigmented rats, and compared this with hippocampal effects. Persistent long-term potentiation (LTP, >24 h) in layer II/III of the primary VC, and LTP in the dentate gyrus, were impaired by application of the mGluR5 antagonist 2-methyl-6-(phenylethynyl) pyridine (MPEP). Long-term depression in VC was unaffected. Twenty-four hours after MPEP treatment, mGluR1a monomer expression was reduced in the VC but not in the hippocampus, whereas dimer expression was unaffected; mGluR2/3 and mGluR5 monomers were unaffected, but dimers were reduced in the VC. Our data suggest that mGluR5 is engaged in the regulation of synaptic plasticity in the adult VC and hippocampus: the mechanisms for this may be quite distinct, however. While only LTP is affected by mGluR5-antagonism in the VC, both LTP and LTD are affected in the hippocampus. Furthermore, the higher sensitivity of mGluR expression to antagonism of mGluR5 in VC compared to the hippocampus suggests that mGluR5 regulates plasticity phenomena in these structures by means of distinct mGluR-dependent processes.     

Kindling induces transient NMDA receptor-mediated facilitation of high-frequency input in the rat dentate gyrus

To elucidate the gating mechanism of the epileptic dentate gyrus on seizure-like input, we investigated dentate gyrus field potentials and granule cell excitatory postsynaptic potentials (EPSPs) following high-frequency stimulation (10-100 Hz) of the lateral perforant path in an experimental model of temporal lobe epilepsy (i.e., kindled rats). Although control slices showed steady EPSP depression at frequencies greater than 20 Hz, slices taken from animals 48 h after the last seizure presented pronounced EPSP facilitation at 50 and 100 Hz, followed by steady depression. However, 28 days after kindling, the EPSP facilitation was no longer detectable. Using the specific N-methyl-D-aspartate (NMDA) and RS-alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproponic acid (AMPA) receptor antagonists 2-amino-5-phosphonovaleric acid and SYM 2206, we examined the time course of alterations in glutamate receptor-dependent synaptic currents that parallel transient EPSP facilitation. Forty-eight hours after kindling, the fractional AMPA and NMDA receptor-mediated excitatory postsynaptic current (EPSC) components shifted dramatically in favor of the NMDA receptor-mediated response. Four weeks after kindling, however, AMPA and NMDA receptor-mediated EPSCs reverted to control-like values. Although the granule cells of the dentate gyrus contain mRNA-encoding kainate receptors, neither single nor repetitive perforant path stimuli evoked kainate receptor-mediated EPSCs in control or in kindled rats. The enhanced excitability of the kindled dentate gyrus 48 h after the last seizure, as well as the breakdown of its gating function, appear to result from transiently enhanced NMDA receptor activation that provides significantly slower EPSC kinetics than those observed in control slices and in slices from kindled animals with a 28-day seizure-free interval. Therefore, NMDA receptors seem to play a critical role in the acute throughput of seizure activity and in the induction of the kindled state but not in the persistence of enhanced seizure susceptibility.     

Kainate receptors in primary afferents to the rat gracile nucleus

The expression of metabotropic glutamate receptor 8 (mGluR8) was studied in the rat hippocampus after pilocarpine-induced status epilepticus (APISE) by light immunohistochemistry and immunoelectron microscopy. At 1 day APISE, mGluR8 immunoreactivity was up-regulated in the entire molecular layer of the dentate gyrus. At 7 days APISE, mGluR8 immunoreactive cells began to appear in the stratum lacunosum moleculare of CA1, and by day 31, they were seen in all layers of CA1. By electron microscopy and double labelling study, the mGluR8 immunoreactive cells were identified as astrocytes. The present novel finding of induced expression of mGluR8 in astrocytes APISE suggests that it may be linked to gliosis.     

Serotonin receptor binding and mRNA expression in the hippocampus of fearful amygdala-kindled rats

Amygdala kindling in rats increases fear behavior. The neural correlates of this fear are not well understood. In this experiment, we investigated the relation between serotonin receptor binding and mRNA expression and fearful behavior in amygdala-kindled rats. Rats received either 100 kindling stimulations or sham stimulations, and their fear behavior was subsequently assessed in an unfamiliar open field. Then, the rats were sacrificed and 5-HT transporter binding, 5-HT1A and 5-HT2A receptor binding, and 5-HT1A mRNA expression in several brain regions was assessed. The kindled rats were significantly more fearful in the open field than the sham-stimulated rats. They also had significantly more 5-HT1A receptor binding and mRNA expression in the dentate gyrus than the sham-simulated rats, and these increases in 5-HT1A receptor binding and mRNA expression were significantly correlated to the increases in fear. There were no significant differences between the kindled and sham-stimulated rats in 5-HT transporter binding or 5-HT2A receptor binding. These results suggest that alterations in 5-HT1A receptors in the dentate gyrus may play a role in the expression of kindled fear.     

听源性惊厥易感大鼠惊厥和点燃后前脑结构内的c—fos表达

为探讨听源性惊厥点燃和前脑结构的关系，用免疫细胞化学方法结合体视学分析，研究Ｗｉｓｔａｒ种系的听源性惊厥易感大鼠惊厥和点燃后，前脑结构内ｃ－ｆｏｓ表达的差异。结果显示，１．正常Ｗｉｓｔａｒ大鼠接受一次强音刺激后，海马，齿状回，杏仁核，内嗅皮质，嗅周皮质和额－顶皮质内未见Ｆｏｘ阳性神经元；２．Ｐ７７ＰＭＣ大鼠一次惊厥后，除海马，齿状回外，上述被检各区内可见广泛的Ｆｏｓ阳性神经元，其分布具有区域差异．     

Expression of the group II and III metabotropic glutamate receptors in the hippocampus of patients with mesial temporal lobe epilepsy

By immunocytochemical study by both light and electron microscopy of the hippocampus of patients with mesial temporal lobe epilepsy, we have shown that mGluR2/3 and mGluR4 immunoreaction product was mainly localised in the molecular layer of the dentate gyrus and CA2 area. Electron microscopy showed that most of the immunoreaction product due to mGluR2/3, 4a and 8 was deposited in the postsynaptic elements of the CA2 pyramidal layer and the inner molecular layer of the dentate gyrus. Only mGluR8 immunoreaction product in the CA2 area and mGluR2/3 in the inner molecular layer of the dentate gyrus were demonstrated in presynaptic elements, suggesting that mGluR2/3 and 8 may be involved in presynaptic inhibition of glutamate release in these areas. The demonstration of some degenerating axon terminals in the inner molecular layer of the dentate gyrus suggests that degeneration of interneurons caused by repeated seizures was still in progress. The finding of mGluR2/3, 4 and 8 immunoreactive astrocytes in patient hippocampus suggests that mGluR2/3, 4 and 8 receptors may be involved in gliosis.     

戊四唑点燃大鼠模型海马结构蛋白激酶C阳性细胞的变化

目的　利用戊四唑点燃大鼠模型 ,研究癫痫大鼠海马结构蛋白激酶C(PKC)阳性细胞的变化。方法　将大鼠分为对照组和模型组 ,模型组大鼠又分为完全点燃组和完全点燃后间歇 2 4h组。用免疫组织化学方法检测了海马和齿状回PKC阳性细胞的变化。结果　PKC阳性细胞主要分布于齿状回的颗粒层 ,在海马的分布主要在分子层 ,数量较少。点燃组大鼠海马和齿状回PKC阳性细胞数量与对照组相比 ,均显著增加 (P <0 0 5 ) ;点燃后间歇 2 4h组与对照组相比 ,无显著性变化 (P >0 0 5 )。结论　PKC阳性细胞表达的增加可能在诱导大鼠点燃中起重要的作用。     

beta-NAAG rescues LTP from blockade by NAAG in rat dentate gyrus via the type 3 metabotropic glutamate receptor

N-Acetylaspartylglutamate (NAAG) is an agonist at the type 3 metabotropic glutamate receptor (mGluR3), which is coupled to a Gi/o protein. When activated, the mGluR3 receptor inhibits adenylyl cyclase and reduces the cAMP-mediated second-messenger cascade. Long-term potentiation (LTP) in the medial perforant path (MPP) of the hippocampal dentate gyrus requires increases in cAMP. The presence of mGluR3 receptors and NAAG in neurons of the dentate gyrus suggests that this peptide transmitter may inhibit LTP in the dentate gyrus. High-frequency stimulation (100 Hz; 2 s) of the MPP resulted in LTP of extracellularly recorded excitatory postsynaptic potentials at the MPP-granule cell synapse of rat hippocampal slices. Perfusion of the slice with NAAG (50 and 200 microM) blocked LTP. Neither 50 nor 200 microM NAAG produced N-methyl-D-aspartate receptor currents in the granule cells of the acute hippocampal slice. The group II mGluR antagonist ethyl glutamate (100 microM) and a structural analogue of NAAG, beta-NAAG (100 microM), prevented the blockade of LTP by NAAG. Paired-pulse depression of the excitatory postsynaptic potential at 20- and 80-ms interpulse intervals (IPI) was not affected by NAAG or beta-NAAG. beta-NAAG did not affect inositol trisphosphate production stimulated by the agonist glutamate in cells expressing the group I mGluR1alpha or mGluR5. beta-NAAG blocked the decrease in forskolin-stimulated cAMP by the group II mGluR agonist (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) but not the group III mGluR agonist L(+)-2-amino-4-phosphonobutyric acid in cerebellar granule cells. In cells transfected with mGluR3, but not mGluR2, beta-NAAG blocked forskolin-stimulated cAMP responses to glutamate, NAAG, the nonspecific group I, II agonist trans-ACPD, and the group II agonist DCG-IV. We conclude that beta-NAAG is a selective mGluR antagonist capable of differentiating between mGluR2 and mGluR3 subtypes and that the mGluR3 receptor functions to regulate activity-dependent synaptic potentiation in the hippocampus.     

Increased glutamate receptor gene expression in the cerebral cortex of insulin induced hypoglycemic and streptozotocin-induced diabetic rats

Hypoglycemia causes brain fuel deprivation, resulting in functional brain failure and brain death. It is a serious complication of insulin therapy in diabetic patients. A single intrafemoral dose of streptozotocin was administered to induce diabetes. Hypoglycemia was induced by appropriate doses of insulin s.c. in control and diabetic rats. Glutamate content and glutamate receptor kinetics were studied using [3H]glutamate. [3H]MK 801 was used to study the NMDA receptor kinetics. NMDA2B and metabotropic glutamate receptor (mGluR) 5 subunits receptor gene expressions were done using real time PCR. There was a significant (P<0.001) increase in the glutamate content in the cerebral cortex of hypoglycemic and diabetic rats when compared with control with more glutamate content in the hypoglycemic group. Scatchard analysis using [3H]glutamate and [3H]MK 801 in the cerebral cortex showed a significant (P<0.001) increase in the maximal binding (Bmax) in both hypoglycemic and diabetic rats when compared with control with no significant change in equilibrium dissociation constant. The glutamate and NMDA receptor binding parameters were significantly (P<0.001) enhanced in the hypoglycemic rats compared with hyperglycemic rats. Real time PCR analysis also showed a significant increase (P<0.001) in the gene expression of NMDA2B and mGluR5 subunits of glutamate receptor. This increased gene expression of NMDA2B and mGluR5 glutamate receptor subunits confirmed the enhanced mRNA of receptor subunits and subsequently at the protein level from the receptor kinetic studies. The enhanced glutamate receptors were more prominent in hypoglycemic group which is of significance in this study. Up-regulation of glutamate leads to Ca2+ overload in cells, potentially leading to cell damage and death. This functional damage during hypoglycemia is suggested to contribute to cognitive and memory deficits which has immense clinical relevance in the therapeutic management of diabetes.